[address-policy-wg] IPv6 access to K-root

On Tue, Mar 01, 2005 at 09:09:18PM +0100, Iljitsch van Beijnum wrote:
> >Unfortunately this mainly leads to bad connectivity as half of the
> >IPv6 world filters /48.
> 
> As long as your two transit ISPs accept the /48 from eachother, you'll 
> have redundancy so this is not fatal.

I consider 15-hop AS_PATHs crossing ponds multiple times and tunnels all
over etc with 500ms+ RTT quite fatal, compared to let's say 3-hop
AS_PATH all native.

> And if we can write up a nice document that outlines how people can 
> filter out "remote" /48s because having those in their routing tables 
> has no added value, while allowing "close by" /48s that help optimize 
> traffic flow, this could work out very well.

No, won't. The problem operators on the net don't update filters, let
alone read "nice documents" how to do things properly. And there is
still:

> But if it gets out of hand, people can filter without breaking 
> connectivity.

Wrong. You cannot filter PA-more-specific-multihomer-prefixes away
without risking to lose connectivity to them. If the provider aggregate
has routing problems (be it interdomain or even intradomain) and your
transit cloud doesn't see the more-specific prefix announced by the
multihomer, you lose connectivity. Especially in the case of the
aggregate falling off the sky. A site behind upstreams who filter
doesn't see the aggregate anymore, and because of filtering don't see
the more-specific anymore too. POOF. There goes your connectivity. You
still rely on the PA provider. You don't want that.

PA-more-specific-multihoming fails (as a viable solution) as soon as
people (especially transits) start filtering more-specifics. And
looking at the IPv6 world today, this is already the case.


Regards,
Daniel

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